The coupler is one of important parts of a railcar, and has a standard connecting contour. It is mainly used to ensure the coupling between cars and achieve operations of train marshalling and car drafting.
Typically, conventional train coupler will be operated in three operating states, i.e., locked state, unlock state and full open state. When a coupler is in the locked state, a coupler knuckle lock stops a coupler knuckle from being opened, and coupled cars cannot be separated spontaneously. For 17-type coupler, when rotating the coupler lifting bar, the coupler knuckle lock is lifted to an unlock position by the lower lockpin rotation shaft and a lower lockpin mechanism which are coupled with the coupler lifting bar, and then the coupler is switched into the unlock state. At this time, the coupler knuckle will be opened under external force and separate cars. When the coupler lifting bar is lifted to the upmost position, the coupler knuckle is pushed to a full open position by the coupler knuckle lock. At this time, the coupler is switched into the full open state, and adjacent cars will be coupled. Two cars may be coupled with each other spontaneously when they are colliding, so as to achieve the train marshalling. When separating the trains, an operator standing outside the end of the car manipulate a coupler lifting bar to unlock coupled couplers, thereby separating two coupled cars. In this way, it can not only improve the operating efficiency of train marshalling, but also ensure the safety of operator. Referring to FIG. 1, a schematic view of operating state of a conventional 17-type coupler is shown.
In hump shunting operation (referring to FIGS. 2a and 2b), an operator standing at the side of railroad line having signal display manipulates a coupler lifting bar such that a rear coupler of a rolling car is in the unlock state. During rolling, on one hand, a speed reducer in the railroad line will decrease the rolling speed of the rolling car so as to ensure that the rolling car will not exceed an allowable speed when coupling; and on the other hand, the rolling car will collide with a standing car when coupling. Thus, under the inertia force of the rolling car, it is possible that the coupler knuckle of the rear coupler of the rolling car may pivot on a coupler knuckle pin in a locked direction. That is, the rear coupler may be in a non-full open position or the locked position, while a front coupler of a subsequent rolling car is in the locked position at this moment. Therefore, after the subsequent rolling car rolls downwardly, the two cars can not be successfully coupled together. Accordingly, the success ratio of coupling in marshalling is decreased, which may affect the operating efficiency in marshalling and also may directly or indirectly affect the safety of operator in operating.
In view of the above disadvantages, there is an urgent requirement to develop a mechanism or member which unlocks a coupler from both sides thereof by means of coupler lifting bars, so as to be applicable to many operating conditions such as hump shunting.